Electric heater and method of manufacturing same.



PATENTED APR. 4, 1905.

I M. 0. BEEEE. ELEGTRIG HEATER AND METHOD OF MANUFACTURING SAME.

APPLICATION FILED MAY 14, 1900.

uvvmron ATTORNEY.

UNITED STATES ratented April 4, 1905.

PAT NT OFFICE.

MURRAY 0. BFEBE', OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO GEORGE WESTINGHOUSE, OF PITTSBURG, PENNSYLVANIA.

ELECTRIC HEATER AND METHOD OF MANUFACTURING SAME- SPECIFICATION' forming part of Letters Patent No. 786,257, dated. April 4, 1905.-

Application filed May 14, 1900. Serial No. 16,601.

To all whont it may concern.-

Be it known that I, MURRAY C.BEEBE, acitizen of the United States, residing at Pittsburg,

in the-county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electric Heaters and Methods of Manufacturing the Same, of which the following is a specification.

My invention relates to electric heaters, and it has particular reference to the heaters employed in electric lamps of the Nernst type and to methods of manufacturing such heaters; but it is not necessarily restricted to use in lamps. I

The object of my invention is to provide an electric heater which shall be more durable than those heretofore vemployed and one in which the conductor shall be effectively protected from contact with other devices and apparatus in. connection-with "which it is used.

A further object of the invention is to provide a simple and inexpensive method of manufacturmg electric heaters for use in connectlon wlth'Nernst lamps or in any other relations in which said devices may be found use:

ful' and desirable.

With these ends in view I have devised a heater, a methodof manufacture, and an apparatus for use in such manufacture, illustrations of which may be found in the accompanying drawings, in which Figure: 1 illustrates the first step in the method of manufacture; Fig.2, the second step inthe manufacture and a sectional view of portions of an apparatus suitable for practicmg this portion of the method; Fig. 3, a

view, on an enlarged scale and partially in side elevationand partially in section, of one form of a completed heater; Fig. 4, a perspective view, partially in section, of another form of completed heater; and Fig. 5, a sectional view of a partially-formed heater constructed in accordance with a modified method.

" It has been a usual practice in constructingheaters for Nernst lamps to wind the heaterwire around a non-conducting core which served as a'permanent support for the wire.

In heaters of this construction the high temperature to which they were subjected in use the turns, or some of them, free from the support, so that they would not maintain their proper relative positions and if moved mto contact with each otherwould establish shortcircuits, and thus materially shorten the life of the heater.

My invention overcomes such difliculties, as will hereinafter appear.

In practicing my invention I wind a flexible wire 1, of suitable conducting metal-such, for example, as platinum and of suitable gage, in a helical coil 2 about a body 3 of such form and dimensions as will give to the coil the desired contour. This body 3 may be a string of any organic material that is readily destroyed when subjected to a high temperature, or it may be otherwise susceptible of removal when the proper period in I the process of manufacture is reached. While the body 3 and the wire'l'are each shown of circular cross-section, it will be understood that either of these parts may have any other I The product of this operation is a string or I rod 8, havinga sheath or envelop 9, of nonconducting and incombustible material, in the interior of which the coil 2 and its core are firmly embedded. I now subject the rod 8 to a high temperature in a suitable oven or furnace, which servesto harden the envelop and to destroy the core, provided it is formed of combustible material. Thisleaves the heater in the form indicated in Fig. 3' and suitable for use. Any shrinkage of the non-conducting material in which the wire h lix is embedded will obviously serve to bin the helix more closely in position, and at the same time the latteris entirely protected from contact nection with which it is used, contact with which might produce injury either tothe heater or to the part with which it should come in contact.

In case ahcater of dit'ferent form from that shown in Fig. 3 is desired the rod 8 may be bent into the desired form while the envelop is in plastic condition and before it is subsirab'le.

My invention is obviously not limited to the jected to heat to harden the envelop and destroy the core. A heater 8, bent into spiral or helical form prior to being baked, is shown in Fig. 4. of the drawings.

In case a heater havinga straight-line axis or one having an axis in the form of a portion of the circumference of a circle 15 desired a core of metal or other incombustible material may be utilized in the manufacture. In Fig. 5 T have shown a metal core 3", provided with a coating 10 of wax or similar material, around which the coil 2 is formed. After the envelop 9, of refractory material, is

applied the application of heat to harden the envelop will soften the wax, and thus permitthe ready withdrawal of the core. Whatever may be the final form of the heater, it will be understood that terminal wires may be attached to the ends of the heater-coil by means of solder or otherwise.

I desire it to be distinctly understood that.

my invention is not limited to the employment of cores having any specific characteristics or to any specific method ofremoving them.

In fact, it may sometimes be found desirable to employ a core of such form and composition that its retention as a permanent part of the heater may be found advantageous.

the heating-coil of an envelop of such compo,-

sition and dimensions as will support and protect the coil, the subsequent steps of bending of the coil and the removal of the core being either added or omitted, as may be found deuse of any specific mechanism nor is it limited to any specific materials or forms, and hence it will be understood that what is shown and described herein is intended to merely' set useful in practice.

I claim as my invention- 1 The method of constructing electric heaters which consists in winding a conductor rsaasv form and dimensions, forming a non-conduct ing, tubular envelop in close contact with said core and coil and completely covering the coil and SUlOJQC'CIIIg the resulting artlcle to a suitciently high temperature to destroy the core J and harden the envelop.

1-. The method of constructing electric heaters which consists in coiling'a flexible conductor around a flexible, combustible core of suitable form and dimensions, forming a noneonducting envelop in close contact with said core and coil and completely covering the latter, bending the resulting article to the desired form and then subjecting it to a sulliciently high temperature to destroy the core and harden the envelop.

5. An electric heater for lamp-glowers comprising a wire helix and a thin, open-ended tube of non-conducting, refractory material in the inner surface of which the said wire helix is wholly or partially embedded.

6. An electric heater for larnp-glowers, comprising a conducting-coil of helical form and a tubulars'upporting and protecting envelop theinternal diameter of which is substantially equal'to that of the coil and the external diameter' of which is slightly greater than that of the coil.

7. The method of constructing an electric heater whichconsists in winding resistancewire in the form of an open helix around a core, then applying a tubular sheath of plastic, heat-resisting :material, then hardening the sheath and finally removing the core.

In testimony whereof I- have hereunto subscribed my name this 11th day of May, A. l).

1900. forth what I have found to be desirable and i MURRAY 0. BEEB'E.

Witnesses:

. HENRY NOEL POTTER,

HUGH ANDREW (BOOKS. 

